<html>
    <head>
        <style>
            *{
                margin: 0;
                padding: 0;
            }
            body{
                width: 200px;
                height: 100px;
            }
            div{
                line-height: 100px;
                font-size: 42px;
                text-align: center;
            }
        </style>
    </head>
    <body>
        <div id="clock_div"></div>
        <script src="js/my_clock.js"></script>
    </body>
</html>